1. Field of the Invention
This invention relates generally to electric motors and, more particularly, to a means of housing a plurality of armatures having similar electrical and magnetic characteristics within a common compact housing structure and means to deliver preselected speed/torque values that may vary from one armature to another.
2. Description of Prior Art
In the past, there have been electric motor packages produced that contain a plurality of armatures within a common housing structure. Devices of this type are shown in U.S. Pat. Nos. 3,463,954, 3,471,729 and 3,510,707. Primarily, motors of this type that are packaged together in a plural form are used in power seat drives for automobiles where movement of the seat in a number of directions is provided. Normally, these directions include fore and aft as well as up and down. A plurality of independently controlled motors for such an application offer advantages over a single motor with required clutches, solenoids and other mechanical paraphernalia to provide the various directions of movement to the seat.
There have been some problems connected with use of a plurality of independently controlled motors that are solved by the present invention. Specifically, considerably more torque is required to raise and lower the backside of a seat due to lifting the weight of the seat and the occupant(s) whose weight is normally concentrated primarily at the backside of a seat than, for example, is required for fore and aft movement. Commonly, for automotive seat mover mechanisms, for example, have used a package of three motors. Prior to the present invention, the options in the design of the motor package were first to either design all three motor sections with torque sufficient to provide the lifting power of the seat or construct one motor in the package differently from the other two in order to provide the required torque. The first option is not desirable due to added cost in material such as magnets and wire on those two of the motors which do not need as much power. The second option is not desirable because of added cost in assembly since the corresponding special parts which differ, such as magnets, armatures, etc. add complications and must be handled separately during assembly. Non-common parts also add cost in stocking more motor components as well as in having to purchase the differing components in lower volumes.